Liquid crystal display (LCD) has the advantages of good image quality, small size, light weight, low driving voltage, low power consumption, no radiation and relatively low manufacturing cost, and is dominant in the field of flat panel display.
Nowadays, liquid crystal display devices are gradually developing towards a wide viewing angle, and liquid crystal display devices such as an in-plane switching mode (IPS) or a fringe field switching mode (FFS) can realize wide viewing angle. However, people in today's society are paying more and more attention to protecting their privacy. There are many things that do not like to share with others. In public places, people want to keep their content confidential when they use a mobile phone or browse a computer. Therefore, the display device with a single viewing angle mode has been unable to meet the needs of the user. In addition to the need for a wide viewing angle, the display device is also desirable to be switched or adjusted to a narrow viewing angle mode when privacy protection is required.
In order to switch the wide and narrow viewing angles of the liquid crystal display device, one way is to apply a vertical electric field to the liquid crystal molecules by using the viewing angle control electrode on the color filter substrate, to thereby achieve a narrow viewing angle mode. Referring to FIG. 1 and FIG. 2, the liquid crystal display device includes a first substrate 11, a second substrate 12 and a liquid crystal layer 13 disposed between the first substrate 11 and the second substrate 12. A viewing angle control electrode 111 is provided on the first substrate 11. As shown in FIG. 1, when displaying in a wide viewing angle, the viewing angle control electrode 111 on the first substrate 11 is applied with no voltage, and the potential difference between the viewing angle control electrode 111 and the common electrode (not shown) on the second substrate 12 is zero, so that the liquid crystal display device realizes a wide viewing angle display. As shown in FIG. 2, when a narrow viewing angle display is required, the viewing angle control electrode 111 on the first substrate 11 is applied with a voltage, which causes a large potential difference between the viewing angle control electrode 111 and the common electrode on the second substrate 12, so that the liquid crystal molecules in the liquid crystal layer 13 are tilted due to a vertical electric field (as indicated by the arrows E) while rotating horizontally, and the contrast of the liquid crystal display device is reduced due to light leakage, to finally achieve a narrow viewing angle display.
In normal display of the liquid crystal display device, the gate driver and the source driver are generally driven by a timing controller. Currently, for matured and mass-produced timing controllers, the image refresh frequency of the images displayed at the output end is equal to the data input frequency of the image data inputted from the input end, and the image refresh frequency for the images cannot be regulated. In the viewing angle switching method mentioned above, when a conventional image refresh frequency of 60 Hz is used, the display panel will have the problems of uneven display (i.e., mura), image sticking and flicker, etc.